“Hallux valgus” or “hallux abducto valgus” is associated with bunion deformity, where “hallux” refers to the great toe, “valgus” refers to the abnormal slant of the great toe, and “abducto” refers to the abnormal slant or inward leaning of the great toe towards the second toe.
The abnormalities associated with bunion development are caused by a biomechanical abnormality, where certain tendons, ligaments, and supportive structures of the first metatarsal are no longer functioning correctly. This biomechanical abnormality may be due to the structure of the foot - flat feet, excessive ligamentous flexibility, abnormal bone structure—or certain neurological conditions.
The treatment of hallux valgus deformity includes an assessment of the hallux valgus angle, the intermetatarsal angle and the contribution of an interphalageus deformity. Additionally, the presence or absence of arthritic involvement of both the first metatarsocuneiform joint and the first metatarsophalangeal joint are also assessed. The orientation of the distal metatarsal articular angle and the orientation of the first metatarsocuneiform joint are also considered.
Various methods to correct the intermetatarsal angle are known. Soft tissue correction can be achieved by suturing the lateral capsule of the first metatarsal to the medial capsule of the second metatarsal, incorporating the intervening, previously released adductor tendon. A loss of reduction can occur due to the forces that oppose the suture repair as well as the possibility that poor tissue quality can contribute to a loss of reduction.
When more rigid deformities of the intermetatarsal angle are present, it is generally reduced by using a distal or proximal osteotomy of the first metatarsal. Typically, a surgeon cuts into the foot near the bunion, and removes the excess growth of bone with a bone saw. Depending on the degree of deformity, the surgeon may need to cut into the bone of the great toe and realign the bones so that the great toe no longer slants to the outside. Improving the angle of the great toe and repairing the metatarsal bones may require a fastening means to hold them in place. The incisions are later closed with stitches, and a bandage is applied.
Such osteotomies can be technically challenging and difficult to perform. Further, the consequences and potential complications from such surgical procedures is a daunting list that includes delayed union, malunion, nonunion, excessive shortening of the first metatarsal, avascular necrosis, hardware failure and prolonged protected ambulation.
There is a need for a bunion repair technique that is simple, flexible and is performed by a minimally invasive lateral approach, with indirect placement of buttons across the first and second metatarsal. Also needed is a suture passing Kirschner wire (K-wire) that is configured to pass small suture between one or two bones without “binding” the suture in the bone tunnel.